Y. Akamatsu

Medial Opening Wedge High Tibial Osteotomy With Early Full Weight Bearing

PURPOSE We performed clinical and radiographic evaluation of patients with medial compartment osteoarthritis of the knee who had undergone treatment with opening wedge high tibial osteotomy (OWHTO) followed by early full weight bearing. OWHTO procedures were performed by use of TomoFix (Synthes, Bettlach, Switzerland) and bone substitute materials. METHODS OWHTO was performed in 57 knees in 52 patients with a mean age of 69 years (range, 54 to 82 years) at the time of operation. The diagnosis was primary osteoarthritis in 34 knees in 29 patients and osteonecrosis in a further 23 knees in 23 patients. We established an early weight-bearing exercise program during which these patients were permitted partial weight-bearing exercise 1 week after their osteotomy procedure. All patients performed full weight-bearing exercises at 2 weeks after surgery. The mean follow-up period was 40 months (range, 24 to 62 months). RESULTS The American Knee Society Score and Function Score showed significant improvement from 50.9 +/- 12.3 to 91.7 +/- 6.9 points and 59.3 +/- 13.1 to 94.1 +/- 8.8 points, respectively. Before surgery, the mean femorotibial angle during standing was 181.3 degrees +/- 2.4 degrees (1.3 degrees anatomic varus), but it measured 169.6 degrees +/- 2.3 degrees (10.4 degrees valgus) at the time of follow-up. There were no instances of nonunion or implant failure in any of our patients. CONCLUSIONS We have shown that an early weight-bearing exercise program enables full weight bearing at 2 weeks after OWHTO with TomoFix and artificial bone wedges. Overall, this combination was a highly successful course of treatment for correcting knee malalignment in patients with medial compartment osteoarthritis. LEVEL OF EVIDENCE Level IV, therapeutic case series.

The extent of degeneration of cruciate ligament is associated with chondrogenic differentiation in patients with osteoarthritis of the knee

OBJECTIVE Degeneration in cruciate ligaments results from abnormal biomechanical stress and the aging process. Such degeneration is a common outcome in patients with osteoarthritis (OA) of the knee and contributes to the progression of OA. However, to date, there are no specific markers that can predict the extent of ligament degeneration. We hypothesized that the extent of degeneration has correlations to increased chondrogenic potential. METHODS Twenty anterior cruciate ligaments (ACLs) and 30 posterior cruciate ligaments (PCLs) from 30 knees of 28 adult patients with OA at the time of total knee arthroplasty were used for the study. Degeneration was histologically assessed using a grading system. Expressions of Scleraxis (as a ligament cell marker) and Sry-type HMG box 9 (SOX9) (as a chondrogenic marker) were immunohistochemically assessed in each grade. RESULTS We found the opposite expression pattern between Scleraxis and SOX9 according to the grade. The percentage of Scleraxis-positive cells decreased significantly by grade (60.9±23.7 in grade 1, 39.7±30.5 in grade 2, and 13.9±27.1 in grade 3, P<0.0001). In contrast, the percentage of SOX9-positive cells increased significantly by grade (2.5±4.9 in grade 1, 17.5±13.4 in grade 2, and 50.9±27.1 in grade 3, P<0.0001). Furthermore, co-localized expression of both Scleraxis and SOX9 was demonstrated in chondrocyte-like cells. CONCLUSIONS This study indicates that chondrogenic differentiation is associated with the progression of degeneration in human ligaments. Our results suggest that the expression of SOX9 as a chondrogenic marker could be an indicator for the extent of degeneration in human ligaments. It remains to be elucidated whether suppression of chondrogenic differentiation can prevent progression of the degenerative process of cruciate ligaments in patients with OA.

Reproducibility of condylar twist angle measurement using computed tomography and axial radiography of the distal femur

INTRODUCTION It is essential to understand rotational alignment of the distal femur when performing total knee arthroplasty (TKA). Several rotational landmarks including condylar twist angle (CTA) are used for preoperative planning and during TKA. Axial radiography of the distal femur is used for measuring the CTA, and assessing rotational alignment in TKA. The aim of this study was to investigate the reliability and the reproducibility of the CTA using two different methods and evaluate if CTA differed between varus and valgus knees and between normal and osteoarthritic knees. MATERIALS AND METHODS CTA were obtained from 144 knees (77 patients) having total knee or hip arthroplasty using computed tomography (CT) and axial radiography. Subjects were divided into five groups based on femorotibial angle (FTA) and into four groups based on the severity of knee osteoarthritis. The intra-observer and inter-observer reliabilities of these methods and inter-method differences were evaluated. RESULTS The mean CTA was 7.02° with axial radiography, and 6.87° with CT images. There were no significant differences among the five FTA groups and among the four osteoarthritis groups. In total, intra-/inter-observer, and inter-method intraclass correlation coefficients were substantial or almost perfect in the scoring system of Landis et al. However, discrepancies ≥ 2° between the two methods were observed in more than 20% of knees. CONCLUSION The CTA should be reassessed by more than two observers or two methods for precise preoperative TKA planning in cases where it is difficult to identify the bony landmarks for CTA measurements. LEVEL OF EVIDENCE Level III.

Should sagittal osteotomy line be parallel to tibial posterior slope in high tibial osteotomy

BackgroundThe reason why the osteotomy line in the sagittal view should be parallel to the medial tibial posterior slope in open wedge high tibial osteotomy (OWHTO) remains unclear. In addition, previous study reported that a posterolateral hinge position led to an increase in tibial posterior slope (TPS) after OWHTO. Our aims were to examine the relationships between angles among the tibial plateau and osteotomy planes or the hinge point and the change in TPS, and the location of the hinge position after OWHTO using three-dimensional computed tomography (3DCT). We hypothesized that the sagittal angle between the tibial plateau and osteotomy planes with an anterior-widening proximal tibial fragment resulted in increased TPS, and the hinge position located posterolaterally.MethodsPreoperative planning anticipated a weight-bearing line ratio of 62% on the radiograph. The anterior gap was 67% of the posterior gap in OWHTO. We identified the tibial plateau and upper and lower osteotomy planes on 3DCT of 82 patients with symptomatic medial osteoarthritic knee after OWHTO. The osteotomy plane angles between the tibial plateau and upper osteotomy planes, and opening gap angles between both osteotomy planes in the coronal and sagittal views were measured. The anteroposterior (AP) and lateral hinge position was displayed as a percentage on the upper osteotomy plane. We assessed the relationships among them.ResultsThe TPS significantly increased after OWHTO (p = 0.002). There was no significant difference between the sagittal osteotomy plane angle and the change in TPS. The sagittal opening gap angle and the AP hinge position ratio were significantly correlated with the change in the TPS (r = 0.477 p < 0.001 and r = − 0.342, p = 0.002, respectively). The hinge position was located a mean of 16.0% from the lateral and 48.6% from the posterior tibial edge in the upper osteotomy plane.ConclusionsContrary to our expectation, the osteotomy plane did not need to be parallel to the tibial plateau plane in the sagittal view. However, the osteotomy gap should be rectangular in the sagittal view. The hinge position located nearly in the center of the sagittal view.

Edoxaban is effective in reducing the incidence of asymptomatic phlebographic events following closed-wedge high tibial osteotomy

INTRODUCTION The purpose of this study was twofold: to investigate whether edoxaban significantly decreases the rate of venous thromboembolism (VTE) following closed-wedge high tibial osteotomy (CWHTO), in terms of phlebographic event, and to determine whether edoxaban is safe or increases the rate of hemorrhagic complications. We hypothesized that edoxaban would decrease the incidence of VTE and would not increase the rate of hemorrhagic complications. MATERIALS AND METHODS We randomly enrolled 60 patients undergoing CWHTO. The patients were divided into two groups: one group receiving edoxaban (15mg in 5 patients, 30mg in 23 patients) and a non-edoxaban group. All patients underwent computed tomography venography on day 7to diagnose postoperative VTE. Blood samples were obtained on the day before CWHTO and on postoperative days 1, 3, 7 and 14. The incidence of VTE and hemorrhagic events in both groups was compared using unpaired Student t-test or chi-square test. RESULTS The incidence of VTE was significantly greater in the non-edoxaban group (31.3% versus 7.1%; P=0.02). The incidence of deep vein thrombosis (DVT) was also significantly greater in the non-edoxaban group (28.1% versus 3.6%; P=0.01). A single patient from the edoxaban group experienced major bleeding. On days 3 and 7, D-dimer levels were significantly lower in the edoxaban group (P=0.03 and 0.003, respectively). On days 3, 7 and 14, activated partial thromboplastin time was significantly greater in the edoxaban group (P=0.02, 0.01 and 0.006, respectively). CONCLUSION Patients undergoing CWHTO are at risk of postoperative VTE. Edoxaban helps prevent asymptomatic phlebographic VTE and DVT following CWHTO; however, the risk of major bleeding must be considered. LEVEL OF EVIDENCE II.

Influence of coronal bowing on the lower alignment and the positioning of component in navigation and conventional total knee arthroplasty

BACKGROUND Coronal alignment is an important factor for the function and longevity of total knee arthroplasty (TKA). Coronal bowing of the lower extremity is common among Asians and it may pose a risk for malalignment of the lower leg and malposition of component. HYPOTHESIS We hypothesized that coronal bowing itself has a risk for malalignment of the lower leg and malposition of femoral/tibial components and that navigation TKA is beneficial for patients with coronal bowing. We investigated the incidence of femoral/tibial bowing in patients treated with TKA and compared the radiographic parameters between the navigation group and the conventional group. Additionally, the influence of coronal bowing on these radiographic parameters was investigated. MATERIALS AND METHODS We enrolled 35 patients with knee osteoarthritis and 70 bilateral simultaneous TKAs. The patients underwent TKA with the use of a computer tomography-free navigation in one knee and conventional TKA in the contralateral knee. Preoperative coronal bowing were measured, and the subjects were divided into 2 subgroups, i.e. the bowing group and the non-bowing group. Lateral bowing was expressed as plus (+) and medial bowing was expressed as minus (-). Various radiographic parameters, including coronal bowing, lower leg alignment, component position, and outliers were compared between the navigation group and the conventional group. RESULTS Femoral bowing varied from -7.4° to 10.9° with an average of 3.0°. Tibial bowing varied from -4.1° to 4.6° with an average of 0.4°. The femoral component was placed more properly in the navigation group. Number of outlier regarding to the coronal femoral component angle to the femoral mechanical axis was 14 cases (37.8%) in the bowing group and 6 cases (18.2%) in the non-bowing group (P=0.04). DISCUSSION In conclusion, coronal femoral bowing has an important effect on femoral bone cut in TKA. The navigated TKA was more consistent than conventional TKA in aiding proper alignments of femoral component. LEVEL OF EVIDENCE Level II, comparative prospective study.

537 CLINICAL RESULTS OF OPEN WEDGE HIGH TIBIAL OSTEOTOMY FOR OSTEOARTHRITIS AND OSTEONECROSIS OF THE KNEE

Purpose: Intra-articular injections in the knee joint are commonly used for therapeutic and diagnostic goals concerning knee pathology. Several approaches are used to establish an intra-articular injection in the knee joint, however accuracy rates differ per approach. The primary objective was to summarize the evidence concerning the accuracy of different approaches for intra-articular injections in the knee. Methods: The literature was systemically reviewed in online databases Pubmed and Embase until June 2009. Two reviewers (JH, MR) independently applied the inclusion and exclusion criteria and inclusion was reached by consensus. Risk of bias of the included studies was assessed independently by 2 reviewers using the QUADAS-tool. Study characteristics, accuracy data, other outcome measures, results and conclusions were independently extracted by 2 reviewers. A trained statistician pooled the accuracy rates per used injection approach. Results: In total, 9 studies were included. The superolateral approach with the knee in extension was studied most (230 injections) and resulted in the highest pooled accuracy of 89% (95% C.I. 85%-93%). Pooling of the medial midpatellar approach, the anterolateral approach and the anteromedial approach resulted in the lowest pooled accuracy rates, respectively in 56% (95% C.I. 46%-68%), 70% (95% C.I. 64%-77%) and 71% (95% C.I. 65%-78%). Conclusion: Based on the results of this systematic review the authors recommend the superolateral approach with the knee in extension for the intra-articular injection of the knee joint.